Control system for hospital bed

ABSTRACT

A control system for a hospital bed includes circuitry for selectively energizing an electrical motor for each function desired to be performed. There is a control panel at the footboard of the bed for use by a nurse or other attendant and a pendant for use by the occupant of the bed. There is a forward and reverse position for each motor, and the circuit connections permit independent control at the footboard panel which may be interrupted by action taken at the pendant. Control of functions at the pendant are of the momentary contact type, and it ceases when the occupant releases a switch. Adjustment of the bed at the footboard, however, continues until a limit position is reached or the occupant intervenes or the nurse actuates a stop or cancel switch. The pendant has priority of control, but the nurse may actuate a switch which locks out control by the occupant yet permits the occupant to maintain ability to interrupt control at the footboard. A level sensitive switch is used to place the bed in a predetermined incline to achieve a Trendelenburg position.

United States Patent 1151 3,697,846

Mueller [451 Oct. 10, 1972 [54] CONTROL SYSTEM FOR HOSPITAL BED [57]ABSTRACT [72] Inventor: Floyd F. Mueller, Two Rivers, Wis. A controlsystem for a hospital bed includes circuitry for selectively energizingan electrical motor for each [73] Asslgnee' st g? ifi SupplyCorporafunction desired to be performed. There is a control 0 an panelat the footboard of the bed for use by a nurse or [22] Filed: Feb. 11,1971 I other attendant and a pendant for use by the occupant of the bed.There is a forward and reverse position for [21] Appl' 114590 eachmotor, and the circuit connections permit independent control at thefootboard panel which may be 52 US. Cl. ..318/544, 318/547, 318/548,interrupted y aetieh thkeh at the Pendent. Centre! of 307 1 5 307 142functions at the pendant are of the momentary contact 51 1m. 01. ..H02p3 00 type, and h ceases when the Occupant releeeeS a 5 Field f Search 1/547 54 544; 307/113 Switch. Adjustment Of the bed at the footboard,how- 307/115 142 ever, continues until a limit position is reached orthe occupant intervenes or the nurse actuates a stop or 56] ReferencesCited cancel switch. The pendant has priority of control, but

the nurse may actuate a switch which locks out con- UNITED STATESPATENTS trol by the occupant yet permits the occupant to maintainability to interrupt control at the footboard. A

"""""" level sensitive switch is used to place the bed in a PrimaryExaminer-Benjamin Dobeck Att0mey-Dawson, Tilton, Fallon & Lungmuspredetermined incline to achieve a Trendelenburg position.

12 Claims, 1 Drawing Figure I20 HEAD M0 OR l2b T l2:

[3a /4 a ,4 KNEE /3 BED MOTOR 1/ I31: 13c I41: MOTOR 14 c CONTROL SYSTEMFOR HOSPITAL BED BACKGROUND OF THE INVENTION 1 Field of the InventionThe present invention relates to control systems for hospital bedswherein the various bed positions are controlled through electricmotors. Power-operated hospital beds normally have a sectionalizedmattress support (whether a spring support or flat panels) wherein thesections are articulatedfor independently controlling a head panel toraise and lower the occupants head, leg panels which raise and lower theoccupants knees, and some means for adjusting the height of the bedrelative to the floor. Further, most such beds are adapted so that theentire mattress support panel can be tilted about a transversehorizontal axis to achieve a Trendelenburg position for treatment ofpatients with certain heart conditions wherein the head of the occupantis positioned below the level of his heart and his feet are raised abovethat level.

2. Known Systems Control systems are known for permitting independentcontrol of the motor which raises and lowers the bed, the motor whichraises and lowers the foot panel and the motor which raises and lowersthe knee crease. There have been suggestions for having two separatesets of controls one for a nurse or other attendant located on thefootboard of the bed, and the other for control by the occupant orpatient. The occupants control usually is in the form of a pendant whichhouses the various switches required for his control and whichcommunicates to the footboard panel by means of a flexible cord in whichthe various wires connected to the pendant are located.

In systems having both an attendants control panel at the footboard andan occupants control pendant, it has become desirable to providemechanisms in which the attendant may inhibit or lock out selectiveoperations of the pendant thereby removing control of certain ones orall of the bed functions by the occupant. Systems using electrical ormechanical interlocks for blocking out the occupants manual control byan attendant include conventional mechanical mechanisms for preventingthe displacement of a switch as well as electrical inhibiting circuitrywhich prevents the transmission of a control signal from the pendant toits associated power motor.

SUMMARY OF THE INVENTION In the present invention, there is controlcircuitry for selectively energizing any of the various electricalmotors to perform a desired function, such as raise or lower the bed,raise or lower the head panel, or raise the knee crease. Further, thereis a control panel at the footboard of the bed for use by an attendantas well as a pendant for use by the occupant of the bed. During normaluse, the pendant has priority of control: that is, if an attendant iscontrolling the functions of the bed at the footboard, the occupant mayinterrupt any such control and himself assume control of the bedfunctions.

The present invention also includes circuitry for inhibiting control ofselected ones or all of the bed functions by the occupant; however, eventhough the occupant cannot control the movements of the bed during thislockout, he may nevertheless inhibit control of those movements by anattendant at the footboard. That is to say, the present system permits adoctor or nurse to inhibit actuation of any or all of the drive motorsby the occupant, but the occupant retains priority of control to theextent that he may inhibit control movements by a person manipulatingthe footboard panel. Thus, the system may be set up so that the occupantmay not alter the disposition of the various elements of the bed, but hecan also inhibit any such alteration by another person if he desires.

A level sensitive switch attached to the bed senses when the bedmattress support is tilted to assume a Trendelenburg position; and thisswitch is arranged to provide the proper Trendelenburg positionautomatically.

Other features and advantages of the present invention will be apparentto persons skilled in the art from the following detailed description ofa preferred embodiment accompanied by the attached drawing whereinidentical reference numerals will refer to like parts in the variousviews.

THE DRAWING The drawing is a schematic diagram showing circuit elements,mechanical switch interconnections, and the separation of elementsbetween the pendant and the footboard control panel.

DETAILED DESCRIPTION The control system of the present invention hasparticular utility in controlling the various functions of the bedstructure disclosed in a copending, co-owned application of Turko andMueller for Invalid Bed Constructionff Ser. No. 49,672, filed June 25,1970.

Turning then to the drawing the elements of the control system normallylocated at the pendant which is within the reach of the occupant of thebed are enclosed within the heavy solid line 10, and those elementswhich are located at the footboard control panel which is within thecontrol of a nurse or other attendant are enclosed within the heavysolid line 11. The system includes a head motor 12 for controlling theraising and lowering of the head panel in an articulated mattresssupport frame, a knee motor 13 for raising and lowering the knee creasebetween an articulated thigh panel and lower leg panel, and a bed motor14 for raising and lowering the entire mattress support frame includingan occupant of the bed, if any. Each of the motors 12-14 comes to a stopalmost immediately when power is removed because they are connected totheir associated loads through gear trains. Thus, the reversing lead maybe energized immediately after the other power load is de-energized.Each of the motors 12-14 has an input power lead and these aredesignated respectively 12a, 13a and 14a. The frame of each of themotors 12-14 is grounded, and each motor further has a forward powerlead (designated 12b-14b respectively) and a reverse power lead(designated l2c-14c respectively).

The leads 12a, 13a and 14a are connected in common to an input powerlead 15 received from a conventional plug 16 adapted to fit into a-cycle, volt ac receptacle. A second power lead connected to the plug 16is designated by reference numeral 17 and it is adapted, according tothe circuit arrangement described herein, to be selectively connected toeither the forward or reverse input power terminal of the motors 12-14.Thus, there are six normally open relay contacts designated respectively20a, 21a, 22a, 23a, 24a and 25a having one contact connected to thepower line 17 and a second contact connected respectively to the motorinput power terminals 12b, 12c, 13b, 13c, 14b, and 14c. The normallyopen contacts 20a-25 are actuated respectively by relays whose coils aredesignated respectively 20, 21, 22, 23, 24 and 25. Associated with eachof the relay coils 20-25 is a second set of normally open contacts, andthese are designated respectively 20b-25b.

All of the elements within the pendant and the footboard control panel11 (except for the power contacts a25a) are operated on six volts, andthis is received from a transformer generally designated by referencenumeral 26 having a primary winding connected across the power lines 15,16 and a secondary winding designated 27. One terminal of the secondarywinding 27 of transformer 26 is directly connected to a line 28, and theother terminal is connected through a resistor 29 and a normally-closedswitch 30 to a line 31. The switch 30 is mechanically actuated by meansof a push button 30a which will open the switch 30 only so long as thebutton 30a is depressed. The switch 30 has two main functions. The firstis to terminate operation of all of the control circuitry from thefootboard panel. Secondly, it breaks any circuits that may have beenestablished from the pendant. The footboard operations are cancelled andmust be re-initiated to effect an operation of the bed, but the pendantoperation is only interrupted. If a patient continues to press a pendantswitch, a circuit will be established when the switch 30 is released.

Turning now to the circuitry which controls the motor 12 which raisesand lowers the head panel, there are two switches 33 and 34 located atthe pendant 10 and actuated respectively by push buttons 35 and 36. Theswitches 33 and 34 are two-position switches having a movable contact, anormally closed contact and an open contact. These switches are of themomentary contact type wherein the associated push button must remain ina depressed state or the switch will reverse to its original position,as shown in the drawing. The removable contact of switch 33 is connectedto the line 31 by means of a wire fed through a flexible cord from thefootboard panel to the pendant. The normally closed contact of theswitch 33 is connected to the movable contact of the switch 34. Thenormally open contact of the switch 33 is coupled through a normallyclosed switch 38 in the footboard panel to one terminal of the relaycoil 20. Similarly, the normally open contact of switch 34 is connectedthrough a normally closed switch 39 to one terminal of the relay coil21. The switches 38 and 39 are sometimes referred to as the lock outswitches, and it is their function to lock out control of the pendantover actuation of the motor 12, although the occupant of the bed stillretains control to inhibit operation of the motor 12 by an attendant atthe footboard.

The other terminal of the relay coil 20 is connected through a set ofnormally closed switch contacts 40a and a normally closed limit switch41 to the line 28 connected to the secondary winding 27 of transformer26. The limit switch 41 is associated with the bed, and it opens whenthe head panel of the bed is raised to a predetermined limit. Similarly,the other terminal of relay coil 21 is connected through a set ofnormally closed switch contacts 43a and a normally closed limit switch44 to the line 28. The limit switch 44 opens when the head panel islowered to a predetermined, horizontal position. The switches 40a and430 are actuated respectively by push buttons 40 and 43, and associatedwith each of these switches is another set of normally closed contactsdesignated respectively 40b and 43b. Thus, for example, when the pushbutton 40 is depressed, the contacts 40a open immediately and shortlythereafter the contacts 40b close. The push buttons 40 and 43 may bearranged so that they toggle about a center line whereby only one pushbutton at a time may activate its associated switches.

The common junction of the coil 20 and switch 38 is connected to thecommon junction of the switches 43b and 20b. Similarly, the commonjunction of the relay coil 21 and switch 39 is directly connected to thecommon junction between the switches 21b and 40b. The common junctionbetween the switches 40b and 43b is connected to a line 46 which, inturn, is connected to the contacts of switches 20b and 21b asillustrated and also to the normally closed contact of the switch 34 inthe pendant 10.

The control circuitry for the knee motor 13 is similar to that justdescribed for the head motor 12, and in addition to the relay coils 22and 23 and their associated contacts, there are first and second lockout switches 50 and 51 connected respectively to one terminal of thosecoils. The other terminal of relay coil 22 is connected through a set ofnormally closed contacts 52a and a normally closed limit switch 53 tothe line 28. The other terminal of relay coil 23 is connected through aset of normally closed contacts 54a and a normally closed limit switch55 to the line 28. The contacts 52a are controlled by a push button 50which also controls a set of normally open contacts 52b. Similarly, thecontacts 54a are controlled by a push button 54 which also controls aset of normally open contacts 54b.

The limit switch 53 is connected to one of the leg panels and it isdesired to open when that panel reaches a predetermined upper position;whereas, the limit switch 55 may be connected to the frame and it isadapted to open when the leg panels reach a lower (horizontal) position.

There are two push buttons, designated 57 and 58 in the pendant 10 forinitiating the forward and reverse direction of the knee motor 13, andeach of these is associated with a two-position switch designatedrespectively 57a and 58a. The circuit connections for the controlcircuitry associated with the knee motor, as already mentioned, issimilar in structure and operation to that disclosed in connection withthe head motor. It will be observed that a line interconnects the line31 through the two normally closed positions of the switches 57a and 58ato the common junction between the switches 526 and 54b as well as tothe switches 22b and 23b. Further, the relay coil 22 is connected inseries with the normally closed switches 52a and the limit switch 53whereas the relay coil 22 is connected in series with the normallyclosed switch 54a and normally closed limit switch 55.

The control circuitry associated with the bed motor 14 is similar,though not identical, to that which has been disclosed in connectionwith the control of the head motor 12. This circuitry is shown to theright of the drawing, and it includes the previously-mentioned relaycoils 24 and 25 and their associated switches (24a, 24b, 25a and 25b).Each coil is connected by means of a normally closed lock out switch (62and 63) to normally open positions of the switches 64 and 65respectively. The switches 64 and 65 are located in the pendant and eachis similar to the previouslydescribed switches 33 and 34, beingcontrolled respectively by push buttons 66 and 67. The normally closedterminal of switch 65 is connected via line 75 to one contact each ofswitches 24 and 25b, the other contacts of which are connectedrespectively to the previouslymentioned terminals of coils 24 and 25.

The other terminal of the coil 24 is connected in series with a set ofnormally closed contacts 68a and a normally closed limit switch 69 tothe line 28; and the other terminal of the relay coil 25 is connectedthrough a normally closed switch 70, a normally closed levelsensitiveswitch 71 and a normally closed limit switch 72 to the line 28. Thejunction between the switches 71 and 72 is directly connected by meansof a line 73 and the filament of a lamp 74 to the line 31. The levelsensitive switch 71 may be a conventional mercury switch attached to themain mattress support frame of the bed which opens when the bed istilted head down and feet up (the Trendelenburg position) to apredetermined incline.

Associated with the contacts 68a and 70a are two push buttons 68 and 70,and these also control respectively the normally open contacts 68b and70b. The limit switches 69 and 72 are opened when the bed isrespectively in its uppermost and lowermost positions. If the bed is tobe operated without the pendant, the pendant can be disconnected fromthe line by means of a disconnect socket; and a plug put into thecontrol socket to complete the circuit from lead 31 to leads 46, 59 and75.

Except for the insertion of the Trendelenburg position sensing switch 71and the lamp 74, the control circuitry associated with the bed motor 14is similar to that provided for controlling the head motor 12, theoperation of which will now be discussed.

OPERATION When an attendant desires to raise the head panel, hedepressed the push button 43 which opens the contacts 430 to deenergizerelay coil 21 if the head panel was being lowered when the push button43 was depressed, and closes the contacts 43b. The closing of thecontacts 43b completes a circuit from the power line 28 through thelimit switch 41 and normally closed contacts 40a to energize the relaycoil 20. It will be observed that this energizing circuit is completedthrough the normally closed positions of the switches 33 and 34 in thependant 14). Thus, the operation or energization of the relay coil isdependent upon the fact that these latter two switches are closed.

When the relay coil 20 is energized contacts 20b are closed to hold therelay coil in an energized state by shorting out the normally opencontacts 43b. Secondly, the relay associated with coil 20 closescontacts 20a and thereby couples the motor power terminal 12b to thepower line 17. Since the motor power line 12a is al ready connected tothe input power line 15, the motor 12 will be driven in a forwarddirection. Because of the holding action of the contacts 20b, the motor12 will be continued in a forward direction after the push button 43 isreleased. This energization of the motor 12 will continue until one ofthe following conditions occurs.

1. The upper limit for the head panel is reached and the limit switch 41is opened to de-energize the relay coil 20;

2. The attendant depresses push button 40 indicating a desire to lowerthe head panel (which action will de-energize relay coil 20 by openingcontacts 40a);

3. The attendant pushes the stop or cancel button 30a to open thecontacts 30 and thereby de-energize the coil 20; or

4. The occupant of the bed depresses either the push button 35 or thepush button 36 which breaks the circuit to the relay coil 20.

The lowering of the head panel, conversely, opens the switch 40a andcloses the switch 40b to complete a circuit through the switches 33, 34,43a and 44 to energize the relay coil 21. This, in turn, closes thecontacts 21b and 21a, the contacts 21b acting as holding contacts toretain the relay coil 21 in an energized state, and the contacts 21aacting to reverse the direction of the motor 12.

Turning now to the control of the head motor 12 by means of the pendant10, if an occupant of the bed depresses the push button 35, the firstthing that happens is that the movable contact of the switch 33 isdisplaced from its normally closed contact, and this breaks the circuitto either of the relay coils 20 or 21 if they had been energized becausetheir energization is dependent upon the fact that both switches 33 and34 are in their normal positions. Next, however, the movable contactengages its normally open position and completes a circuit through thelock out switch 38 to energize the coil 20 through the normally closedswitches 40a and 41. The motor 12 is energized as already describedthrough the contacts 20a which are closed when the relay coil 20 isenergized. The motor 12 continues to operate until one of the followingconditions occurs:

1. The limit switch 41 is opened indicating that the head panel hasreached the full extent of its travel;

2. The occupant releases the push button 35 thereby returning the switch33 to its normal position and de-energizing the coil 20;

3. An attendant or other person depresses the cancel or stop button 30ato open the switch 30 and temporarily interrupt the circuit to the coil20; or

4. The attendant pushes the button 40 to open the contacts 40a andtemporarily interrupt the circuit to the coil 20.

It will be observed that if an attendant pushes the stop or cancelbutton 30a and then releases it, the head motor will resume operation inits forward direction as long as the occupant continues to depress thepush button 35 until the head panel has run its full extent and thelimit switch 38 opens. There is a similar operation with theinterruption of pendant control by the push buttons on the footboardcontrol panel. That is to say, the cancel button 30a and the controlpanel UP/DOWN buttons only interrupt and do not cancel a functionoriginating at the pendant.

Directing attention now to the lock out switches 38, 39 associated withthe head motor 12, when these switches are opened by manual operation ofan attendant at the footboard panel, the occupant of the bed is not ableto energize either of the coils 20, 21 by means of the switches 33, 34.The attendant is still able to maintain control over the head motor 12by means of the footboard control panel switches 40, 43. However, theoccupant does have control to the extent that he can inhibit operationat the footboard panel. For example, supposing that the attendant hasdepressed the push button 40 to thereby cause the relay coil 21 to beenergized and locked in in a manner already described. The occupant mayde-energize that coil by pressing either of the switches 33, 34 at thependant which will interrupt current flow through the line 31, causingthe coil 21 to be de-energized and the contacts 21b to open. Similarly,if the forward control relay coil is energized at the footboard panelwhile the lock out switches 38, 39 are open, depressing either of thehead control push buttons 35, 36 at the pendant will cause that forwardcontrol coil to be de-energized and drop out of the circuit. In thisconnection, it will be observed that it is the opening of the nonnallyclosed switch contact of the switches 33, 34 which causes the droppingout of an associated relay coil, not the closing of the normally opencontact of those switches.

All of the lock switches 38, 39, 50, 51, 62 and 63 may be mechanicallyinterconnected so as to be opened or closed simultaneously, or theswitches may be grouped in pairs, if desired such that an attendantcould selectively lock out control of either the head motor, knee motor,or bed motor, or any combination of them.

The operation of the control circuitry associated with the knee motor 13and the bed motor 14 is substantially the same as that which has justbeen described, except that in the control circuitry of the bed motor14, provision is made for achieving the Trendelenburg position. In orderto understand the manner in which the Trendelenburg position is reached,reference is made to the copending application identified earlier.

Briefly, that application discloses an invalid bed having a pair of sidescissors linkage mechanisms for raising and lowering an upperpatient-support frame relative to a base frame. Movement of thepatient-support frame into the Trendelenburg or reverse Trendelenburgpositions is achieved by buckling corresponding links in each of thescissors linkage mechanisms. To achieve the Trendelenburg position, thebed is raised to its highest position and the lower ends of the scissorslinkage at the foot end of the bed are blocked against movement so thatwhen the bed motor 14 is energized to move the bed down by pushing thebutton 70, the scissors frame will buckle and the head section willlower until the level sensitive switch 71 opens when the patient-supportframe has achieved a predetermined inclination relative to thehorizontal. When switch 71 opens, it breaks the circuit to coil 25,thereby opening contact a and shutting down the bed motor 14.

Although it is not the case for the bed of the aboveidentifiedapplication, a similar technique could be used to achieve a reverseTrendelenburg position by placing a level sensitive switch in serieswith relay coil 24.

The lamp 74 is energized when the light switch 71 is closed, indicativeof the fact that the bed is not in its lowermost position. The switch isopened when the bed reaches its lowest level-thus breaking the lightcircuit. This light serves as a signal, for example, in a darkened roomto a nurse or attendant that the bed is not in its lowest position whichis normally considered the safest position for most patients especiallyduring the night.

Persons skilled in the art will be able to modify certain of thestructure which has been illustrated and to substitute equivalentelements for those which have been disclosed; and it is, therefore,intended that all such modifications and substitutions be covered asthey are embraced within the spirit and scope of the appended claims.

I claim:

1. In a system for controlling a motor in a power operated bed, saidmotor. connected to move a section of said bed, the combinationcomprising: first switch means actuatable by an attendant for connectinga source of electrical energy to energize said motor to move said bedsection; second switch means actuatable by an occupant of said bed forconnecting said source of electrical energy to energize said motorindependently of said first switch means; lock out circuit meansconnected in circuit with said second switch means and actuatable by anattendant to selectively inhibit operation of said second switch meansto energize said motor; and circuit means interconnecting said firstswitch means and said second switch means whereby said second switchmeans is capable of inhibiting operation of said first switch means evenwhen said lock out circuit means is actuated to inhibit said secondswitch means from energizing said motor.

2. The system of claim 1 wherein said system further comprises afootboard control panel at which said first switch means is located; andpendant control means for housing said second switch means.

3. The system of claim 2 wherein said first switch means includes arelay having a coil and normally open contacts connected in series withsaid motor and said source of power; a push-actuated switch connected incircuit with said coil to energize the same when said push switch isactuated by an attendant; and limit switch means associated with saidbed for opening the circuit to said coil when said bed section hasreached a predetermined position, said second switch means beingconnected in circuit with said coil to energize the same when saidsecond switch means is closed independent of the closing of said firstswitch means.

4. The system of claim 3 wherein said second switch means includes atwo-position switch having a movable contact, a normally closed contactand a normally open contact, said system further comprising meansinterconnecting said normally closed contact with said push switch meansfor disconnecting said relay coil when said movable contact isdisconnected from said normally closed contact of said first switchmeans, said normally open contact of said first switch means beingconnected in series circuit with said lock out circuit means and saidrelay coil to energize said relay coil through said lock out circuitmeans independently of said first switch means.

5. A control system for a power-operated bed including a reversiblemotor controlling the movement of said bed section, comprising:attendant control means fixed to said bed including forward switch meansactuatable by an attendant for energizing said motor in a forwarddirection including means for locking in said forward switch means onceactuated; reverse switch means for energizing said motor in a reversedirection and including means for locking in said reverse switch meansto continually energize said motor once actuated; first limit switchmeans to de-energize said motor when said bed section reaches apredetermined extent of travel in response to the actuation of saidfirst switch means; second limit switch means for deenergizing saidmotor when said bed section has reached a second predetermined level ofextent of travel in response to the actuation of said reverse switchmeans; means electrically interconnecting said reverse switch means andsaid forward switch means whereby the operation of each of these switchmeans is mutually exclusive of the other; occupant control meansincluding a forward switch for energizing said motor in a forwarddirection and a reverse switch for energizing said motor in a reversedirection; and lock out switch means for inhibiting the actuation ofsaid forward and reverse switch means at said pendant control meanswhile permitting said pendant control switch means to inhibit theactuation of said control panel forward and reverse switch means.

6. The system of claim wherein each of said forward and reverse switchmeans of said pendant control means is a two-position switch having anormally closed contact and a normally open contact, said normallyclosed contacts being interconnected when said forward and reverseswitches are in their normal positions and said interconnected positionsbeing connected in series with both of said relay coils whereby both ofsaid relay coils will be de-energized when either of said forward andreverse pendant control means switches is actuated.

7. The system of claim 5 further comprising conductive means forinterconnecting the normally open position of each of said forward andreverse switch means of said pendant control means in series with a lockout switch directly to a terminal of an associated relay coil wherebyactuation of either of said forward or reverse switches of said pendantcontrol means will vest control of said system in the occupant of saidbed provided said lock out switches are closed.

8. A control system for a power-operated bed having a reversible motorfor moving a section of the bed between a first and a second limitposition comprising: a control panel at the footboard of said bed andincluding a forward and a reverse switch actuatable by an attendant,each such switch including a set of normally open contacts and a set ofnormally closed contacts, a first and a second limit switch arranged toopen respectively at said first and said second limit positions of saidsection, a forward and a reverse relay each including a coil and a pairof normally closed contacts; means connecting said sets of normally opencontacts of said forward and reverse relays respectively with theforward and reverse terminals of said motor; a pendant control included,a forward and a reverse switch each including a movable contact, anormally closed contact, and a normally open contact; first conductivemeans for connectin the movable contact and normally closed contact 0said pendant forward switch, said normally open contacts of saidfootboard forward switch, the coil of said forward relay, the normallyclosed contacts of said footboard reverse switch, and said first limitswitch in series across a source of electrical power; second conductivemeans for connecting the movable contact and said normally closedcontact of said pendant reverse switch, said normally open contacts ofsaid footboard reverse switch, the coil of said reverse relay, thenormally closed contacts of said footboard forward switch, and saidsecond limit switch in series across said source of power; thirdconductive means connecting the normally open contacts of said pendantfor-ward switch in parallel with the normally open contacts of saidfootboard forward switch; and fourth conductive means connecting thenormally open contacts of said pendant reverse switch in parallel withthe normally open contacts of said footboard reverse switch.

9. The system of claim 8 further comprising a first lock out switchconnected in series with the normally open contacts of said pendantforward switch to inhibit functioning of the same when said first lockout switch is open and a second lock out switch connected in series withthe normally contacts of said pendant reverse switch to inhibitfunctioning of the same when said second lock out switch is open.

10. The system of claim 8 wherein each of said relays further includes apair of normally closed contacts connected to hold their associatedrelay coils energized when the said associated relay is first energizedby its associated footboard switch.

11. The system of claim 8 further comprising means connecting thenormally closed contacts of said pendant forward and reverse switches inseries with each other and interposed between the source and the forwardand reverse relays of said footboard panel.

12. The system of claim 8 further comprising a level sensitive switchopen when horizontal and closed when tilted to a predetermined degreefrom the horizontal attached to said bed to sense when the mattressframe is displaced from a horizontal position; and means electricallyconnecting said level sensitive switch in series with one of said relaycoils to inhibit energization of the same when the mattress is displacedfrom the horizontal.

1. In a system for controlling a motor in a power operated bed, saidmotor connected to move a section of said bed, the combinationcomprising: first switch means actuatable by an attendant for connectinga source of electrical energy to energize said motor to move said bedsection; second switch means actuatable by an occupant of said bed forconnecting said source of electrical energy to energize said motorindependently of said first switch means; lock out circuit meansconnected in circuit with said second switch means and actuatable by anattendant to selectively inhibit operation of said second switch meansto energize said motor; and circuit means interconnecting said firstswitch means and said second switch means whereby said second switchmeans is capable of inhibiting operation of said first switch means evenwhen said lock out circuit means is actuated to inhibit said secondswitch means from energizing said motor.
 2. The system of claim 1wherein said system further comprises a footboard control panel at whichsaid first switch means is located; and pendant control means forhousing said second switch means.
 3. The system of claim 2 wherein saidfirst switch means includes a relay having a coil and normally opencontacts connected in series with said motor and said source of power; apush-actuated switch connected in circuit with said coil to energize thesame when said push switch is actuated by an attendant; and limit switchmeans associated with said bed for opening the circuit to said coil whensaid bed section has reached a predetermined position, said secondswitch means being connected in circuit with said coil to energize thesame when said second switch means is closed independent of the closingof said first switch means.
 4. The system of claim 3 wherein said secondswitch means includes A two-position switch having a movable contact, anormally closed contact and a normally open contact, said system furthercomprising means interconnecting said normally closed contact with saidpush switch means for disconnecting said relay coil when said movablecontact is disconnected from said normally closed contact of said firstswitch means, said normally open contact of said first switch meansbeing connected in series circuit with said lock out circuit means andsaid relay coil to energize said relay coil through said lock outcircuit means independently of said first switch means.
 5. A controlsystem for a power-operated bed including a reversible motor controllingthe movement of said bed section, comprising: attendant control meansfixed to said bed including forward switch means actuatable by anattendant for energizing said motor in a forward direction includingmeans for locking in said forward switch means once actuated; reverseswitch means for energizing said motor in a reverse direction andincluding means for locking in said reverse switch means to continuallyenergize said motor once actuated; first limit switch means tode-energize said motor when said bed section reaches a predeterminedextent of travel in response to the actuation of said first switchmeans; second limit switch means for deenergizing said motor when saidbed section has reached a second predetermined level of extent of travelin response to the actuation of said reverse switch means; meanselectrically interconnecting said reverse switch means and said forwardswitch means whereby the operation of each of these switch means ismutually exclusive of the other; occupant control means including aforward switch for energizing said motor in a forward direction and areverse switch for energizing said motor in a reverse direction; andlock out switch means for inhibiting the actuation of said forward andreverse switch means at said pendant control means while permitting saidpendant control switch means to inhibit the actuation of said controlpanel forward and reverse switch means.
 6. The system of claim 5 whereineach of said forward and reverse switch means of said pendant controlmeans is a two-position switch having a normally closed contact and anormally open contact, said normally closed contacts beinginterconnected when said forward and reverse switches are in theirnormal positions and said interconnected positions being connected inseries with both of said relay coils whereby both of said relay coilswill be de-energized when either of said forward and reverse pendantcontrol means switches is actuated.
 7. The system of claim 5 furthercomprising conductive means for interconnecting the normally openposition of each of said forward and reverse switch means of saidpendant control means in series with a lock out switch directly to aterminal of an associated relay coil whereby actuation of either of saidforward or reverse switches of said pendant control means will vestcontrol of said system in the occupant of said bed provided said lockout switches are closed.
 8. A control system for a power-operated bedhaving a reversible motor for moving a section of the bed between afirst and a second limit position comprising: a control panel at thefootboard of said bed and including a forward and a reverse switchactuatable by an attendant, each such switch including a set of normallyopen contacts and a set of normally closed contacts, a first and asecond limit switch arranged to open respectively at said first and saidsecond limit positions of said section, a forward and a reverse relayeach including a coil and a pair of normally closed contacts; meansconnecting said sets of normally open contacts of said forward andreverse relays respectively with the forward and reverse terminals ofsaid motor; a pendant control included, a forward and a reverse switcheach including a movable contact, a normally closed contact, and anormally open contact; first conductive meAns for connecting the movablecontact and normally closed contact of said pendant forward switch, saidnormally open contacts of said footboard forward switch, the coil ofsaid forward relay, the normally closed contacts of said footboardreverse switch, and said first limit switch in series across a source ofelectrical power; second conductive means for connecting the movablecontact and said normally closed contact of said pendant reverse switch,said normally open contacts of said footboard reverse switch, the coilof said reverse relay, the normally closed contacts of said footboardforward switch, and said second limit switch in series across saidsource of power; third conductive means connecting the normally opencontacts of said pendant for-ward switch in parallel with the normallyopen contacts of said footboard forward switch; and fourth conductivemeans connecting the normally open contacts of said pendant reverseswitch in parallel with the normally open contacts of said footboardreverse switch.
 9. The system of claim 8 further comprising a first lockout switch connected in series with the normally open contacts of saidpendant forward switch to inhibit functioning of the same when saidfirst lock out switch is open and a second lock out switch connected inseries with the normally contacts of said pendant reverse switch toinhibit functioning of the same when said second lock out switch isopen.
 10. The system of claim 8 wherein each of said relays furtherincludes a pair of normally closed contacts connected to hold theirassociated relay coils energized when the said associated relay is firstenergized by its associated footboard switch.
 11. The system of claim 8further comprising means connecting the normally closed contacts of saidpendant forward and reverse switches in series with each other andinterposed between the source and the forward and reverse relays of saidfootboard panel.
 12. The system of claim 8 further comprising a levelsensitive switch open when horizontal and closed when tilted to apredetermined degree from the horizontal attached to said bed to sensewhen the mattress frame is displaced from a horizontal position; andmeans electrically connecting said level sensitive switch in series withone of said relay coils to inhibit energization of the same when themattress is displaced from the horizontal.